


A Captain's Duty

by AXEe



Category: Star Trek: The Original Series, Supergirl (TV 2015)
Genre: Alternate Universe - Canon Divergence, Alternate Universe - Star Trek Fusion, Established Astra/Alex Danvers, F/F, F/M, Gen, I Don't Even Know, enjoy nonetheless
Language: English
Status: In-Progress
Published: 2020-03-13
Updated: 2020-03-19
Packaged: 2021-02-28 21:27:54
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 5
Words: 4,053
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23123998
Author URL: https://archiveofourown.org/users/AXEe/pseuds/AXEe
Summary: A captain's duty is to her crew and ship first and foremost...
Relationships: Astra/Alex Danvers, James "Jimmy" Olsen/Kara Zor-El, Lucy Lane/Winn Schott Jr., Minor or Background Relationship(s)
Comments: 12
Kudos: 13





	1. The Burdens of Command

**Author's Note:**

> Hello all! Here's a GD/Star Trek fusion AU. Why you ask? Why not. Enjoy :=)

******

**Rao Station, in orbit over Krypton  
Sector 450, Rao System  
Stardate: 2269.01**

The Constitution-class vessel hung against the inky backdrop of the stars, the image broken as tiny flickers of light danced across its hull, illuminating the vessel’s name and registry.

**U.S.S. ATHENA  
NCC-1800**

Standing before the wide viewport, Captain Astra In-ze—the first Kryptonian Starfleet captain—examined the image before her, sighing as she remembered the events of the past week…

******

**One week earlier…**

******

_“Captain’s Log: The_ Athena _has been exploring an uninhabited system on the edge of Federation space. Preliminary scans have indicated a large deposit of uridium on the fourth planet in this system. Myself, ship’s CMO Dr. Danvers, and Ensign Zor-El are currently leading a survey team on the planet’s surface…”_

******

The planet was rocky, the sandy and rocky earth a nearly-uniform beige in color, making for a monochromatic environment. Only the bright colors of the landing party’s uniforms broke the monotonous color.

Standing on a short rise overlooking the valley, Captain Astra In-ze frowned as she examined the landing party.

“You keep staring like that you’re liable to set someone on fire”

Turning, Astra smirked at her CMO.

“I could you know” she remarked.

“Under a yellow sun, yes, you could,” Dr. Alex Danvers nodded “now what’s captured your attention so much?” she mused as she peered down into the valley, quickly spotting the object of Astra’s attention “well,” she shrugged “Ensign Zor-El seems to be settling in nicely” she remarked.

“Does she?” Astra wondered.

“Well, as much as the second Kryptonian in Starfleet can that is,” Alex shrugged. She smirked up at Astra “you know, I remember another Kryptonian ensign who beat herself up over every mistake” she remarked.

“Starfleet doesn’t tolerate mistakes” Astra pointed out.

“But they don’t tolerate their officers killing themselves trying to succeed,” Alex countered “look,” she sighed “I’ve known you for _twelve years_ , Kara’s practically my family too, but she’s not that cute little girl who hung onto your every word anymore. She’s got to make her own way”

Sighing, Astra turned back to focus on her niece who stood amidst the gaggle of red-shirted security officers, Kara Zor-El’s blue sciences division uniform standing out in stark contrast as she examined a few soil samples with her tricorder.

“What’s that?” Alex suddenly asked.

Turning back, Astra looked to where Alex was pointing across the valley, where something moved amidst the rocks. Suddenly there was a sharp whistle as a bright bolt of green light flew down onto the valley floor, striking one redshirted officer square in the chest, knocking him back with a pained yell to flop onto the sand in an inelegant sprawl, unmoving.

Breaking out into a sprint, Alex and Astra raced down the sandy slope, tucking and rolling behind a low sandbank as more weapons fire rained down on them as the landing party ran for cover, some returning fire with their phasers.

“What the hell is going on?!” Alex demanded, drawing her own phaser and taking aim.

“Wrong question, Alex,” Astra panted out “the real question is: what’s going on up there?” she nodded up at the sky, where the _Athena_ hung in orbit…

 ******

In orbit, the U.S.S. _Athena_ was rocked from side-to-side as a group of small ships battered her shields. Seated in the captain’s chair, First Officer Lucy Lane dug her fingers into the armrests as the ship shuddered around them.

“Any response to our hails?!” she demanded.

“No response!” communications officer Vasquez reported as another volley of weapons fire hit, the ship shuddering.

“Bridge to Engineering, Winn! Get me more power to the shields!” Lucy barked into the comm.

“ _On it, Bridge!_ ” Winn called back.

Turning back towards the helm, Lucy grit her teeth.

“James, keep us in orbit” she ordered.

“Aye!” James Olsen replied as his fingers flew over the helm controls.

“Vasquez, keep trying to raise the landing party!” Lucy ordered as another volley of weapons fire hit, the small ships swinging around for another pass…


	2. Wolf in Sheep's Clothing

**Notes for the Chapter:**

> Double update! Chapter TWO! Enjoy! :=)

******

Down on the planet’s surface, Astra ducked as another blast of disruptor fire rained down from the hills. Lining up her phaser, she returned fire, the blue beam of energy lancing across the valley to strike one of the still-unseen assailants, a figure suddenly tumbling down the steep sandy hill.

But despite that one success, more fire rained down on them, the attackers quickly concentrating their fire.

“Spread out!” Astra called out “spread out!!” she repeated as the landing party broke cover, running desperately across the open valley floor, frantically dodging the explosions of dust and rocks, one member of the security team falling back with a pained yell.

Turning, Ensign Kara Zor-El paused, quickly running back towards the fallen officer only to be pitched back by another blast, the impact knocking her back.

“ _Kara!!_ ” Astra turned at her niece’s yell, frantically rushing back over to her, Alex on her heels. Crouching down, Alex pulled her tricorder free, examining the wound on Kara’s upper leg.

“No serious damage,” she reported “but we need to get her back to the ship”

“Captain!”

Astra turned at the call, watching as one of the landing party pointed to where a small ship was suddenly lifting off, its dull hull a near-perfect match for the surrounding environment.

“Report!” Astra barked out as an officer approached.

“Three dead,” the officer panted “communications are still being jammed, probably from some type of device on the surface”

“Find it, destroy it,” Astra ordered. As the officer jogged off, she glanced over at Alex as the Human applied a hypospray to Kara’s injured leg “keep an eye on her,” she ordered as she stood up and sprinted to where the one fallen attacker now lay in the sand.

Keeping a tight grip on her phaser, she assessed him. He was Humanoid, male, with dark skin. Swinging out a leg, Astra kicked his weapon away from him before quickly gripping the front of his shirt and hauling him up.

“Who are you and why did you attack us?” she demanded.

Panting for breath, the man grinned weakly at her.

“We are…vengeance,” he panted out “for you crimes, you shall pay” then, with a muted groan, he flopped back, unconscious. Scowling, Astra dropped him, absently putting her phaser away as her communicator beeped.

“ _Communications blackout cleared. Full communications with the ship have been restored, Captain_ ”

“Understood,” Astra replied, quickly switching channels on the device “In-Ze to _Athena_ , report”

“ _Captain,_ ” Lucy greeted “ _are you all right?_ ”

“More or less,” Astra muttered “status report, Commander”

“ _We were attacked by several unknown vessels,_ ” Lucy explained “ _they took on a smaller vessel from the surface and are feeling the system at warp_ ”

“Acknowledged, beam us up and then lay in a pursuit course,” Astra replied “maximum warp,” she glanced at the unconscious man by her feet “we also have an injured prisoner, take all necessary precautions. In-Ze out”

******

In short order, the landing party was back aboard and the _Athena_ was streaking away from the planet at high-warp. Settling into the captain’s chair, Astra took a breath as she assessed the bridge crew.

“Status, Mr. Olsen?” she asked.

“We’re still behind them,” James reported “but we’re closing fast. At this rate, we’ll actually overtake them in less than ten minutes” he explained.

“Good,” Astra nodded as she looked towards her chief engineer “Mr. Schott, damage report?”

“Minor buckling on the shields on decks thirteen and fourteen, but no serious damage” Winn reported.

“And our friends out there?” Astra wondered.

“They’re small ships, probably originally merchant ships,” Winn explained “they can run rings around us at sublight, but we’re faster at warp”

“What about their weapons?” Astra asked.

“Old-fashioned _lasers_ if you can believe that,” Winn chuckled “nothing we can’t handle” he assured her.

“I’ll hold you to that” Astra muttered.

“Captain, they’re dropping out of warp” James suddenly announced.

“Stay with them,” Astra ordered, her hands automatically tightening their grip on the chair’s armrests “red alert, shields up. Lt. Vasquez, open hailing frequencies”

“Still no response to our hails, Captain” Vasquez reported.

“Keep trying” Astra ordered.

“They’re coming about,” James reported “they’re charging weapons”

“Target phasers, low-intensity yield,” Astra ordered “target their weapons and propulsion systems, try to warm them off”

“Aye, Captain”

On the main viewscreen, Astra watched as the beam of phaser energy struck one of the attacking ships, which violently spun out of control, part of it burning

“Mr. Olsen, you call that ‘warning them off’?” Astra scowled.

“Sorry, they’re more fragile than they look” James apologized as the remaining ships swooped in over the _Athena_ , firing a full volley.

“Shields holding,” Winn announced as the ship shuddered. He shook his head in clear disbelief as the aliens continued their attack “it’s like we’re being attacked by…puppies” he muttered.

“Maybe so, but even puppies have teeth,” Lucy reminded him as another shudder ran through the ship “they’re focusing their attack on our starboard nacelle strut” she reported.

“So, they’re smart,” Astra reasoned “Vasquez, any reply?”

“No, ma’am,” Vasquez shook her head “all communications are being blocked, heavy subspace interference from an unknown source” she explained.

“Try to clear it,” Astra ordered “Bridge to sickbay”

“ _Sickbay here_ ” Alex replied.

“Alex, how’s our guest doing?”

“ _Minor injuries,_ ” Alex reported “ _seems pretty calm_ ” she added.

“Good,” Astra nodded even though Alex couldn’t see her “escort him to the bridge, let’s see if he can talk to our friends out there”

“ _On our way_ ”

In a few minutes, the turbolift was sliding open, Alex and two security guards escorting their prisoner onto the Bridge. Standing up, Astra approached him/

“I’m Astra In-Ze, Captain of the _Athena_ ” she introduced herself.

The alien scowled at her.

“I am J’onn J’onzz,” he proclaimed “and that is all you will get out of me,” he crossed his arms defiantly as he looked around the room “impressive,” he remarked “are you mercenaries, or Luthor’s newest toy?”

“What?” Astra asked “I have no idea what you’re talking about?” she demanded “we don’t work for anyone named ‘Luthor’, we represent the United Federation of Planets, we’re on a peaceful mission of exploration” she explained as a violent explosion lit up the viewscreen, one of the attacking ships suddenly exploding in a massive fireball.

“ _Murder!!!_ ” J’onn J’ozz lunged for Astra, quickly being held back by the security guards “ _two hundred people on each ship! Women! Children! Families!_ ”

“We didn’t fire!” James objected.

“Another vessel incoming!”

“On screen!” Astra ordered, feeling a chill go through her as another vessel appeared.

Another _Starfleet_ vessel.

“Astra,” Alex asked quietly “is that one of ours?”

“Yes,” Astra nodded slowly “I’m afraid it is”


	3. The Natural Order of Things

**Notes for the Chapter:**

> Chapter THREE! Enjoy! :=)

******

The other Starfleet vessel was a Constitution-class starship like the _Athena_ but appeared to have been heavily modified, some type of heavy armor plating had attached to the hull and the warp nacelles had been modified as well, but the fact remained that it was a Starfleet ship.

On the Bridge of the _Athena_ Astra took a breath, watching as the other ship easily picked off the smaller ships one by one.

“Vasquez” she called out.

“Registry coming in now, sir,” Vasquez replied “NCC-1601, U.S.S. _Cadmus_. She was reported missing nearly twelve years ago under the command of Captain Lillian Luthor”

“Luthor?” Astra turned to look first to Vasquez and then to J’onn J’onzz. Gritting her teeth, she scowled at the other ship on the viewscreen “extend our shields to cover Mr. J’onzz’s people,” she ordered “stand down from red alert,” she nodded at the security guards “let him go”

As the two guards released him, J’onn J’ozz looked at her in clear confusion.

“This isn’t a trick?” he asked, clearly stupefied.

“Mr. J’onzz, this is a nightmare,” Astra replied “the _Cadmus_ , how long?” she demanded

“Almost two years now,” he answered slowly “you mean, you really don’t know?”

“Unfortunately no,” Astra shook her head “Lt. Vasquez, give Mr. J’onzz access to communications, see if he can convince his people that we’re not the enemy here,”

As J’onn J’onzz was escorted to the communications station, Astra turned to Alex.

“Pull every file we have on Lillian Luthor and the crew of the _Cadmus_ from the Starfleet Medical database,” she ordered “let’s try to find out just what the hell is going on here”

“Copy that” Alex nodded, making her way towards a station.

“Commander Lane,” Astra called “change our prefix code, now”

“Already done” Lucy replied as hard impact shook the ship.

“ _Cadmus_ has opened fire,” James reported “they’re targeting us now”

“Red alert! Return fire,” Astra ordered “Mr. Olsen, alternate our speed and course, try to keep them guessing”

“Aye, Captain”

“Vasquez, status?” Astra barked out.

“Mr. J’onzz’s ships have called off their attack, but the _Cadmus_ is still not responding to our hails” Vasquez reported.

“Then try to access their main computer,” Astra ordered “shut down their weapons. Barring that, try to get me their log entries”

“Aye”

“Mr. Olsen, photon torpedoes, deck fourteen, section 2-A”

“Torpedoes locked”

“Fire”

On the viewscreen, the bright orange starburst streaked across the void, striking the other ship in the secondary hull.

“Direct hit” James announced.

“That’s it?” Alex asked as she came over, a datatape in one hand.

“It’s a weapons coolant subsystem,” Astra explained “they can fix it, but it’ll take time. In the meantime, what’d you find?”

“Not much,” Alex handed her the datatape “it’ll take a few hours to go through every performance review and psyche evaluation” she explained.

“We don’t have a few hours,” Astra sighed “we need to solve this and fast. Vasquez, could we send a feedback pulse through the comm array? Overload their sensors?”

“We could,” Vasquez nodded “but, it’d would probably knock out our own sensors too, we’d both be blind” she warned.

“It’s a risk that we’ll have to take,” Astra declared as the ship shuddered again “do it”

“Aye, Captain”

Outside the ship, an invisible wave of rippling energy suddenly surged from the _Athena_ to strike the _Cadmus_.

“That’s it, we’re both blind as bats” Lucy reported in the sudden silence that immediately followed.

“Captain,” Vasquez called “ _Cadmus_ is hailing us”

“Thought that would get their attention,” Astra muttered, standing up “on screen”

As the viewscreen cleared, the image of a woman appeared. She was Humanoid, middle-aged, dressed what appeared to the tattered remains of a Starfleet uniform.

Astra looked towards J’onn J’onzz.

“Luthor?” she asked.

“Yes” he hissed.

Turning back, Astra cleared her throat.

“This is Astra In-Ze, captain of the Federation starship _Athena_ ,” she announced “who am I speaking to?”

The other woman smiled, it was a cruel smile, devoid of any warmth or real emotion.

“ _This is Lillian Luthor, captain of the free starship_ Cadmus _, and you, Captain In-Ze are interfering in the natural order of things_ ” she replied…


	4. Mistakes

**Notes for the Chapter:**

> Chapter FOUR! Enjoy! :=)

******

The bridge of the _Athena_ was suddenly as silent as an ancient tomb, all eyes on the two captains as both women continued to stare at one another through the main viewscreen. Leaning back in her chair, Astra adopted a causal, relaxed pose.

“Well now, Captain, you’ll forgive me if I’m not exactly up to date on the state of affairs in this sector,” she began “for example, you said that you’re the captain of the ‘free starship _Cadmus_ ’, how is your ship ‘free’ exactly?”

On the viewscreen, Captain Lillian Luthor adopted a similar pose, mimicking Astra.

“ _Myself and my crew no longer recognize the authority or legitimacy of the Federation or Starfleet_ ” she explained.

“I see,” Astra nodded slowly “and why is that, may I ask?” she had to keep Luthor talking; as long as she was talking she wasn’t ordering her crew to attack.

“ _Come now, Captain,_ ” Luthor chuckled “ _we both know that you’re merely stalling for time until your crew can restore your sensor capability_ ”

Astra shrugged, as if the matter was little consequence to her.

“Perhaps,” she acknowledged “so, the other ships out there, why attack them?” she wondered “in fact, why _continue_ to attack them for the past two years?”

“ _That’s a…private matter between myself and Mr. J’onzz’s people, I’m afraid that you’ll have to ask him_ ” Luthor replied.

“I’m asking you” Astra countered.

“ _And I’m declining to answer,_ ” Luthor replied. Behind her, one of her crew signaled to her “ _we’ll talk again soon, Captain_ ” she promised, before the viewscreen went dark.

As soon the viewscreen went blank, Astra was out of her chair.

“Alex, get down to sickbay and go through those files, I want to know everything about that woman and her crew, and why they would do something like this,” she ordered as she made her way to the turbolift “Mr. Olsen, keep us moving but make sure that Mr. J’onzz’s people stay behind our shields, I don’t want the _Cadmus_ to get a clear shot”

“Aye” James replied.

“Commander Lane, you have the conn. If anyone needs me, I’ll be in main engineering” Astra announced as the turbolift doors slid shut.

Settling down into the captain’s chair, Lucy sighed.

“Guess I’d better warn Winn she’s coming” she muttered…

******

Alex grunted as she reached out and steadied a wobbling beaker as the ship shudder once again. The _Cadmus_ it appeared had decided to start firing blind until their sensors came back up. Or possibly their sensors were already back up and they were targeting the _Athena_ again. Or it could even have been J’onn J’onzz’s people taking potshots at whichever ship they could, it could honestly be anyone of the three for all Alex knew, despite being married to the captain no one told her anything unless it was related to medical needs.

Eyeing the beaker wearily, she inserted the next datatape into her console.

“Computer, scan entry for any psychological profiles or notes pertaining to any mental instabilities” she ordered.

“ _Working…estimated to completion: two hours, forty-three minutes_ ”

“Ay,” Alex rolled her eyes “proceed,” she instructed the system as she got up and made her way to where her most recent patient rested. Kara was sitting up on the biobed idly kicking her legs as Alex came over.

“How’re you feeling?” she asked as she scanned Kara’s recently-healed leg.

“OK” Kara shrugged.

“Liar,” Alex accused softly “I’m asking as your aunt-in-law, not your doctor” she explained as she settled down besides Kara on the bed.

“I screwed up” Kara stated.

“Oh yeah,” Alex nodded “definitely, you heard someone cry out in pain and went back to help. Terrible. And I’m sure that, right now, in the middle all this craziness, your aunt is drawing up your transfer papers right now. Yep, you are officially, the worst person in existence”

“Stop it,” Kara muttered “it’s not funny”

“You’re right,” Alex nodded “it’s not. People make mistakes, Kara, it’s just a part of life. _Even_ people who were genetically engineered from birth and grown in a genesis chamber,” she smiled “besides, I remember another Kryptonian officer who beat herself up over every little mistake,” she stood up, giving the girl a pat on the shoulder “go on, get out of here,” she told her “ah,” she pulled Kara to a stop when she jumped up “rest, you’re officially off-duty. That’s an order”

“Yes, _Doctor_ ” Kara grumbled as she slipped out of the room…

******

“Captain, I’m telling you, it won’t work” Winn repeated as Astra followed him through the engine room.

“You also said that it had never been done before,” Astra reminded him “so, how do you know that it won’t work?”

“Because the relays weren’t designed to handle that amount of energy,” Winn exclaimed “we could channel every ounce of power in the ship to the phasers and all it would do is blow out the entire system”

“We need a way to punch through that armor,” Astra reminded him “get started, that’s an order, Mr. Schott”

Winn sighed, making a note on his PADD.

“Aye, Captain,” he muttered as she turned to leave “if this doesn’t work, I quit” he called out after her.

Astra paused in the door, turning to smirk at him.

“I’ll make a note in my log” she chuckled…

**Notes for the Chapter:**

> Fun fact: According to Star Trek canon, genetic engineering is illegal in the Federation, so Krypton would have to have had abandoned the whole Codex and genesis chamber to become a member


	5. Hope

**Notes for the Chapter:**

> Chapter FIVE! Enjoy! :=)

******

Astra looked up at the chime.

“Come” she called, the doors to her quarters sliding open to reveal her CMO and wife. Smiling at the sight of the other woman, Astra felt some of her tensions ease. She was young enough to remember what Krypton had been like before they encountered the Federation, the rampant environmental collapse, the food shortages, the steady-failure of the Codex and the genesis chamber, and the aggressive overtones from Daxam, and then, like something out of an ancient myth, they had made first contact with the Federation, with the flagship of Starfleet no less, the U.S.S. _Enterprise_ under the command of Captain Christopher Pike.

Despite having warp-capability for well over a century, Krypton had had little interest in space exploration, but with the hope that the Federation represented, they had grabbed at the proverbial brass ring with both hands, within a year of their membership being approved, a third of Krypton’s population had gone off-world, Astra among them.

But Astra was one of the exceptions to that rule; for she was the first Kryptonian enter Starfleet Academy, the first to achieve the rank of captain, and the first to marry a Human.

Due to the dire straits that Krypton had been in, the Federation had begun a sponsorship program, whereby individuals who decided to leave the planet were sponsored by various families from across the Federation, to help ease the largely-isolationist Kryptonians into the wider galaxy. For Astra and her sister and niece, their sponsors had been the Danvers family on Earth, and Earth! What a difference from Krypton! So clean, no crime, no food shortages, and the people were so welcoming; Humans and the dozens of other species had been very welcoming to the newcomers, even more surprising when one learned of Earth’s tumultuous past, the Holocaust, the Eugenics Wars, World War Three and the resulting post-atomic horror, and despite all of that, humanity had managed to not only rebuild, but restore themselves.

For Astra, her hope had been found in one Alexandra Danvers, the girl who would become a surrogate sister to Kara would also become Astra’s lover and now wife.

Settling back in her chair, Astra smirked at her wife.

“Well now, what brings you by, Doctor?” she chuckled.

“Ship’s business, I’m afraid,” Alex replied “a crewmember needs some counseling from her captain”

Frowning, Astra stood up and followed the unusually-silent Alex out into the corridor and into the turbolift…

******

As the doors to her quarters slid open, Kara Zor-El leapt off her bunk and snapped to attention.

“At ease, Kara,” Astra told her tiredly “something tells me that this talk will be more personal in nature,”

Settling down on the bunk besides her niece, Astra sighed, trying to gather her thoughts.

“I’m not going to show you favoritism,” she began “and I can’t either, doing so may diminish my respect among the crew. But, I’d like to think that I’m not being unusually harsh on you either,” she shook her head “Alex tells me that you’ve been beating yourself up over what happened on the planet”

Kara nodded stiffly.

“I couldn’t just leave him there!” she hissed angrily.

“And I wouldn’t expect you to,” Astra nodded “both as your aunt and as your captain. That being said, you shouldn’t have just rushed in there without thinking. Part of being an officer, both in the Military Guild and in Starfleet, is to know when to run and when to fight, and back there was a time to run. You could have called to one of the security officers or any other, more experienced member of the landing party rather than just charging in and endangering your own life,”

She took a breath.

“However, both on and off the record, I have _never_ been more proud of you,” she admitted “and there’ll be both a citation for merit and for disobeying orders in your records” she explained.

Kara blinked.

“Thanks?” she asked, but a small smile played at her lips.

“You’re welcome,” Astra chuckled “go on, get some rest. You’re off duty for the rest of your shift”

Smiling widely now, Kara pulled her aunt into a firm hug…

**Author's Note:**

> Let me know what you thought :=)


End file.
